C/C++ Question Pass reference/instance of an existing B4R library to constructor

Johan Schoeman

Expert
Licensed User
RLiquidCrystal is an existing library in B4R. How would one wrap the below constructor to pass it to a wrapper for LcdBarGraph and how would one then pass rLiquidCrystal from B4R to LcdBarGraph?

B4X:
// -- constructor
LcdBarGraph::LcdBarGraph(LiquidCrystal* lcd, byte numCols, byte startX, byte startY)
 

Erel

Administrator
Staff member
Licensed User
1. You need to use the placement constructor. See how B4RLiquidCrystal::Initialize is implemented. Specifically the use of (backend).

2. Your class should accept a B4RLiquidCrystal parameter and then get the hidden (see the h file) public lc field.
 
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